Generalized scheme of the main biogeochemical fluxes between state variables in the BALTSEM model


BALTSEM, the BAltic sea Long-Term large Scale Eutrophication Model is a time-dependent ecosystem model developed by BNI Sweden and available through the Nest Decision Support System.


For further informaion contact:

* Bo Gustafsson

* Oleg Savchuk

* Bärbel Müller-Karulis

Importance of biogeochemical cycles for the Baltic Sea ecosystem

All the major aspects of the Baltic Sea ecosystem, such as eutrophication, food web dynamics, fishery, susceptibility to pollutants and biodiversity, as well as their responses to climate changes, are both affected by- and reflected in the nutrient biogeochemical cycles.

As a tool for studying these problems, BALTSEM has been under development since the 1990s (read more: about BASYS¹and BASYS²) and is now freely available for both hindcast and forecast simulations via the Baltic Nest Decision Support System (download manual herePDF (pdf, 28.6 MB)).

BALTSEM simulates seasonal ecosystem dynamics driven by all the major transport mechanisms and nutrient biogeochemical fluxes in the Baltic Sea, which is presented as a chain of 13 highly vertically resolved but horizontally averaged water columns and underlying sediments. 

Detail formulations of BALTSEM and model-data comparisons are presented here.

Key model for the BSAP development

BALTSEM has been used as the major scientific tool for development of the HELCOM Baltic Sea Action Plan and is now being expanded to describe the carbon cycle and dynamics of the Persistent Organic Pollutants.

Other examples of the recent BALTSEM implementation include simulation of the long-term development of the Baltic eutrophication since 1850, as well as its participation in the ensemble modelling of the climate change projections.

Furthermore, BALTSEM has also been used as a generator of the input data for benthic and food-web modelling


Read more about the expansions to BALTSEM: BALTSEM-C and BALTSEM-POP, which researchers at BNI Sweden have made here.

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Web editor: Marmar Nekoro

Updated: 2014-03-17
Baltic Nest Institute Sweden
Baltic Sea Centre, Stockholm University
SE-106 91 Stockholm, Sweden, +46-8-16 37 18
Baltic Nest Institute Denmark
Aarhus University, Fredriksborgsvej 399
DK-4000 Roskilde, Denmark, +45 4630 1200
Baltic Nest Institute Finland
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FI-00251 Helsinki, Finland, + 358 20 610 123